As is well known in the art, hard disk drives are data storage devices that typically employ magnetic or optical media to store data. The media is traditionally one or more disks, which contain concentric tracks that are capable of storing data. The disk drive contains a read/write head for each disk surface, and the read/write head is positioned over a particular track in order to read and/or write data to the track. The disk drive positions the read/write head over the appropriate track using servo information which is contained in the tracks. Servo reading is done with one read/write head at a time, while servo writing may be done with multiple read/write heads simultaneously. Each data track contains servo information in multiple locations to aid in the positioning of the read/write heads when reading/writing customer data.
Conventionally, in the context of magnetic media, servo information is written to the storage media using a servo track writer. As will be understood, a servo track writer is an expensive piece of capital equipment. The servo track writer includes hardware which is able to finely position the read/write heads in the disk drive and write servo track information to the magnetic media. Even though a dedicated servo track writer writes servo information to multiple disk surfaces simultaneously, the process of servo track writing can be relatively time consuming, since the magnetic media typically contain many thousands of data tracks each of which contain servo information written in multiple locations. However, because of their expense, disk drive manufacturers rely on as few servo track writers as possible to operate a manufacturing facility.
As will be understood, in manufacturing operations it is highly desirable to reduce manufacturing times and capital expenditures, in order to reduce the total cost of the hard disk drive. In order to help reduce the amount of capital equipment required for disk drive manufacture, and to help reduce manufacturing time, some manufacturers have begun using the disk drive itself to write servo track information, without requiring, or reducing the use of a dedicated servo track writer. Such a process is referred to herein as a self servo write (SSW) operation. While SSW can help reduce the number of servo track writers required in a manufacturing operation, thereby reducing cost, problems can result.
For example, as mentioned above, it is common for disk drives to contain more than one magnetic disk, with many designs including four (4) disks, resulting in eight (8) surfaces which are capable of storing data. Thus, eight read/write heads are present in such a disk drive. Moreover, the power supply used to operate the read/write heads during normal operation is designed only to supply enough power for one read/write head to operate at any given time. This creates a power supply problem when performing SSW, as it is beneficial and preferable to operate all of the read/write heads simultaneously to write servo information on each surface simultaneously, in order to minimize the amount of time required for SSW. Furthermore, it is common to write servo information in partial data track steps, thus requiring multiple passes to completely write the servo information for a data track. Thus, performing such a SSW operation can take a significant amount of time if it is accomplished one disk surface at a time. One way to reduce the amount of time required for SSW operations is to provide the disk drive with a higher capacity power supply capable of supplying enough power to operate all of the read/write heads simultaneously. This supply could be internal to the disk drive, and be included on each drive that is shipped. However, the added power is only required in the factory during the SSW operation to write multiple surface servo information, and not during normal customer data operations. Thus, a larger on board power supply would add a significant amount of cost to the disk drive, ultimately increasing the cost of the disk drive for the customer. Thus, it would be beneficial to perform a SSW operation using more than one read/write head simultaneously in the factory, while still providing the hard disk drive with a power supply optimized for a customer's use to operate one read/write head at a time.
One method which may be used to perform SSW with more than one read/write head simultaneously is to provide the disk drive access to an external power supply, which remains in the factory and does not ship on each drive. The disk drive manufacturer may use the external supply to power multiple read/write heads during SSW operations. The smallest adequate power supply on-board the disk drive to read and write with only one head is delivered to the customer, allowing the customer to pay only for the capability they need. The cost savings to the customer results from a reduced bill of materials and the reduced use of factory capital equipment. However, a problem arises in such a situation related to access to the external power supply. More specifically, providing an access point for the external power supply to connect to the disk drive may result in an unintended electrical connection between adjacent contacts which, in turn, may cause significant damage to the disk drive.
Typically, when manufacturing a hard disk drive, the components of the disk drive are assembled into a casting, which results in two available surfaces which may be used to provide an external electrical connection, namely, the back edge and the top. Furthermore, during manufacture, it is generally beneficial to place disk drives in racks when doing testing and servo track writing operations, thus leaving the back edge as the most convenient surface to use as the electrical connection to the external power supply. The back edge of disk drives generally contain electrical connections, which are contained in an edge-to-edge connector or interface, commonly known as a three-in-one connector. Such a three-in-one connector is widely used and incorporates an advanced technology attachment (ATA) connector recommended standard.
One form of a three-in-one connector is illustrated in FIG. 1. The three-in-one connector 20 contains contacts in three different areas. The three-in-one connector 20 contains power contacts 24, jumper contacts 28, and logic contacts 32. The power contacts 24 include contacts which connect to a power output from a power supply associated with the equipment in which the hard disk drive is installed, such as a personal computer. The jumper contacts 28 typically include contacts to components within the hard disk drive. A shorting jumper may be used to short two adjacent contacts together, and enable or disable certain features within the disk drive, such as master or slave operation. The logic contacts 32 include contacts which are operable to transmit data to and from the disk drive for storage and retrieval. The power contacts 24 and the logic contacts 32 have a standardized configuration, leaving the jumper contacts 28 as a logical location for the connection to the external power supply. The jumper contacts are defined and commonly used by manufactures to customize disk drive operation. However, since the jumper contacts 28 provide an electrical connection to components within the hard disk drive, if a contact for the external power supply is connected to another contact within the jumper contacts 28, severe damage to the components of the disk drive may result. Thus, it would be beneficial to have a contact for providing necessary power for performing a SSW operation, while also protecting the disk drive from damage which may result from an unintentional electrical connection between the power contact and another contact.
While the above-description is directed toward disk drives, it will be understood by those of skill in the art that similar problems exist in other industries. For example, certain computer components, such as, for example, a component containing an electronic erasable programmable read only memory (EEPROM), may require a voltage or current to be applied during manufacture that is not required for normal device operation by a customer. Thus, the present invention has broader applicability than disk devices and could be used with, for example, a portable electronic device which may include an EEPROM which is programmed with the operating system for the device. The EEPROM is programmed using a programming voltage which is greater than the normal operating voltage for the device. Accordingly, it would be advantageous to have a contact for providing necessary power for programming the device, while also protecting the device from an unintentional electrical connection between the power contact and another contact, which may cause damage to the device.
Accordingly, it would be advantageous to have a hard disk drive capable of performing a SSW operation using more than one read/write head simultaneously. It would be beneficial for the manufacturer to simultaneously write servo information for two or more read/write heads (known as a stagger write), or all read/write heads simultaneously (known as a full bank write). It would also be advantageous for such a disk drive to have a power supply optimized for normal operation of the read/write heads that use one read/write head at a time, thus helping to reduce the cost of the disk drive. Furthermore, it would be advantageous for such a disk drive device such as an optical drive or portable electronic device to have an electrical contact for connection to a temporary external power supply which has a relatively small likelihood of inadvertent contact with other electrical contacts to minimize potential damage to the disk drive or other electrical component.